Poly(trimethylene ether)glycol and its uses have been described in the art. Known methods for preparation of a poly(trimethylene ether)glycol involve acid catalyzed polycondensation of 1,3-propanediol. Sulfuric acid is commonly used as a catalyst.
Catalyst systems including an acid and base have been used to produce polyether polyol. (US Patent Publications Nos. 2005/0272911A1 and 2007/0203371A1.)
Processes for manufacturing poly(trimethylene ether)glycol are known. However, it is can be difficult to produce polyol with molecular weight greater than 2000. Extended polymerization times, higher amount of acid catalyst, and higher reaction temperatures can be used to achieve relatively high molecular weight poly(trimethylene ether)glycol, but these process conditions incur higher energy costs, longer cycle times and higher final product color. The presence of color is undesirable for some applications.
The present invention provides processes for making relatively high molecular weight polymeric poly(trimethylene ether)glycol. The processes use a polycondensation co-catalyst system.